By Larry Fine

NEW YORK, Sept 26 (Reuters) - Usain Bolt, who shattered the world record each time to capture Olympic gold in the 100 metres, 200 and 4x100 relay, dismissed speculation his sudden rise to supremacy was aided by doping.

"I know I'm clean. I work hard for what I want," the Jamaican told Reuters in a telephone interview on Friday.

The 6-foot-5 (1.96-metre) sprinter clocked 9.69 seconds for the 100 in Beijing last month to carve 3/100ths of a second off the previous record he set in New York on May 31.

Bolt had previously run only a handful of 100s and his performance raised eyebrows among some observers.

Carl Lewis, a nine-times Olympic champion who won one of his titles when Jamaican-born Canadian Ben Johnson tested positive for steroids at the 1988 Seoul Games, raised questions about Bolt in a recent interview in Sports Illustrated magazine.

"I'm still working with the fact he dropped from 10-flat to 9.6 in one year," American Lewis was quoted as saying.

"I think there are some issues ... countries like Jamaica do not have a random (dope control) programme so they can go months without being tested."

Bolt felt such speculation came with the territory.

"I know what he said," said the Jamaican. "To me it doesn't really matter what he said, a lot of people were saying that.

"When you run the 100 metres that's what you get. As long as you're fast they start saying that.